Archival materials and packaging

ABSTRACT

A layered material containing a buffer and optionally containing an adsorbent. The material may also include a vapor barrier. The material is used for the preservation of archival documents and objects. 
     A container configured to permit the long term storage of documents without slippage of the documents or resulting deformation may also be made from the material.

FIELD OF THE INVENTION

This invention relates to archival materials and the preservation ofarchival materials such as documents or other objects. Morespecifically, it relates to packaging and other articles of manufacturewhich can be used to assist in the preservation of archival documentsand objects.

BACKGROUND OF THE INVENTION

Many attempts have been made to protect container contents from thedeleterious effects of both outside elements and from residual chemicalswithin the container material itself.

Schoettle, U.S. Pat. No. 1,773,064, discloses a cardboard containerwherein the inner layer of cardboard is coated with an acid in order toprotect the contents of the container from alkaline fumes emitted fromthe adhesive used in container construction and/or sealing.

Palmer etal., U.S. Pat. No. 1,564,707, and Flynn, U.S. Pat. No.2,144,453, both relate to packages specifically designed forphotographic film. In the former, the wrapping comprising the containeris substantially free from sulphur, ammonia, and turpentine. In thelatter, there is a black, opaque outer layer and an inner layer which isdescribed only as "inert towards light-sensitive, photographicemulsions".

Hutter, U.S. Pat. No. 2,534,201 discloses a container having metalcorrosion inhibiting characteristics. This is achieved through the useof an inner layer comprised of both an organic amide and an inorganicmetal nitrate.

Fox et al., U.S. Pat. No. 2,555,031, discloses a container for storingphosphatic fertilizers for extended periods by coating the inner layerof the container with a lime material.

Hollinger, U.S. Pat. No. 4,489,120, discloses a boxboard comprising afirst layer of paperboard consisting of non-buffered, substantially purealpha-cellulose and an alkaline size, a second layer of a paperboardcomprising alpha-cellulose, an alkaline buffer and an alkaline size and,intermediate said first and second layers, a layer of water-impermeableplastic. Hollinger states that the inner layer is non-buffered in orderto avoid damage to the contents of containers made from the boxboard.

A study by Parks et al. entitled "Studies on the Degradation Products ofPaper with and without Pollutants in a Closed Environment: I.Preliminary Results", issued in 1990 by the National Institute ofStandards & Technology (NIST), states that for papers aged in thepresence of SO₂, "High performance liquid chromatography (HPLC) onaqueous extracts showed eight peaks from the newsprint aged with SO₂ andsix peaks in the absence of SO₂. Of the eight components found innewsprint aged in SO₂, six were tentatively identified as 2-ketoglutaricacid, malic acid, malonic acid, succinic acid, formic acid, and aceticacid. In the absence of SO₂, four acids were tentatively identified(malonic, succinic, formic and acetic acids)." The study tentativelyidentified two acids in a rag paper as malonic and succinic acid. Thecomponents included: 2-ketoglutaric acid [HOOCCO(CH₂)₂ COOH], malicacid, malonic acid [CH₂ (COOH)₂ ], succinic acid [(CH₂)₂ (COOH)₂ ],formic acid (HCOOH), and acetic acid (CH₃ COOH).

The study shows the existence of problems related to SO₂ and otherpollutants in archival containers. Also, in Table 1 on page 16 of theNIST study, the data shows that newsprint aged in air has a foldingendurance of 4.9 double folds at a 600 gm load, and only 1.9 folds whenaged with SO₂ in the air. Similarly, the rag paper aged in air survived34 double folds at a 1000 gm load, while the rag paper aged in SO₂ andair survived only 10.5 folds at this load.

The NIST paper also states that "Sulfur dioxide absorbed into paper fromthe atmosphere is a suspected precursor of in situ hydrolysis throughthe formation of sulfurous acid, sulfuric or possible analogues withanhydrocellulose units." It is known that oxides of nitrogen combinewith moisture to form nitric acid, and that these pollutants and othersattack other artifacts such as photographs. Sulfur compounds causesilver images, e.g. in photographs or microfilm and microfiche, to fadeas the metallic silver is converted to silver sulfide. Acids attack allof the components of the photograph; they can bleach the silver image,causing evident fading, and they can attack the paper and gelatinsupport, which can become brittle. Peroxides in concentrations as low asone part in thirty million can cause image oxidation and fading.

Other by-products of deterioration found by other researchers includelow molecular weight ketones, aldehydes and phenols. The NISTresearchers also discuss problems associated with trapped by-products ofdeterioration, stating that "Degradation products with significant vaporpressure at room temperature are kept in by the sealing of the papers ina container. The diffusion of these degradation products can occur in avariety of ways. They may become air borne and attach themselves toanother paper or to another site on the same paper encouragingdegradation there."

In the area of archival preservation, i.e., the preservation of papers,photographs, textiles and artifacts of historical, aesthetic orsentimental significance, containers have historically been fabricatedfrom papers developed for the long-term preservation of paper documents.However, it has been discovered that stored archival materials producevarious by-products of deterioration which accelerate the deteriorationprocess. Moreover, various harmful pollutants, such as sulfur dioxide,are readily able to pass through conventional archival boxboards, andtheir entry is not prevented by alkaline materials contained in suchboxboards. Even though the archival paper may absorb such pollutants, itwill later release them and permit them to react with the artifactscontained therein.

Further, it has been observed that the actual configuration of thecontainer may also contribute to the deterioration process. Generally,if the container utilized for the long term storage of archivaldocuments is only partially filled, the archival documents stored insidewill have a tendency to slide down across the bottom of the containerand assume a curved shape. Over a period of time, this results inpermanent deformation of the documents in a curved condition which makesthem subject to cracking when removed, thus accelerating thedeterioration process. In the past, attempts to prevent this curvedcondition have included stuffing crumpled paper in the open space of thecontainer to maintain the documents in a flat condition and prevent themfrom sliding down and curving.

Accordingly, it is an object of the present invention to provide acontainer made from paper which does not contain substances that willdeteriorate and release compounds which will be harmful to archivalmaterials stored therein. It is a further object of the presentinvention to provide a durable container which will substantiallydiminish problems associated with accelerated deterioration of archivalmaterials produced by the deterioration by-products of such materials.An additional object of the present invention is to provide a containerwhich will permit the long term storage of documents without slippage ofthe documents or the resulting deformation. Other objects of the presentinvention will become apparent from the following description and thepractice of the invention.

SUMMARY OF THE INVENTION

The objects of one aspect of the present invention are achieved byproviding a layered material for the preservation of archival documentsand objects which comprises a buffered second layer, a buffered firstlayer and a vapor barrier positioned between the first layer and thesecond layer.

Preferably, the first and/or second layers are buffered with calciumcarbonate, magnesium bicarbonate or a mixture thereof. Preferably, thevapor barrier comprises a layer of polyester, and the polyester ispreferably metallized. Preferably, the first layer further comprises anadsorbent such as activated carbon. Preferably, the first layercomprises at least 10% by weight of the adsorbent based on the totalweight of the first layer. More preferably, the layer contains at least20% by weight of the adsorbent. Preferably, the first layer comprises anamount of a buffering agent which ranges from 2 to 5% by weight based onthe total weight of the first layer. More preferably, the amount ofbuffering agent ranges from 3 to 4% by weight. Preferably, the secondlayer has a smooth and durable finish, and comprises fibers of northernsoftwoods. The material can further comprise a porous layer, wherein thefirst layer is positioned between the porous layer and the vaporbarrier. Preferably, the porous layer is substantially free of theadsorbent, in order to avoid contact between, e.g., activated carbon andthe archival documents or objects stored therein. Preferably, the porouslayer contains a buffer and comprises a high quality fiber such ascotton, northern softwood or eucalyptus fibers. The porous layer ispreferably free from lignin and sulfur. The porous layer can alsocomprise an adsorbent such as activated carbon. Both the first andsecond layer preferably have a neutral to alkaline pH, preferablyranging from 8.5 to 9.2.

The objects of another aspect of the present invention are achieved byproviding an article of manufacture such as an archival document orother object, or a container for storing the archival documents orobjects, in which the article comprises a buffer and an adsorbent. Thefollowing preferred variants of this aspect of the invention relate toboth the container and the article.

The buffer and the adsorbent may be interspersed in a single layer ofthe article, or the buffer and the adsorbent can instead be contained intwo or more distinct layers. Preferably, the article is substantiallyfree from lignin and sulphur. Preferably, the article is buffered withcalcium carbonate, magnesium bicarbonate or a mixture thereof, and issealed with a vapor barrier, which comprises a layer of polyester ormetallized polyester. Preferably, the adsorbent is activated carbon, andthe article comprises the adsorbent in an amount which is at least 10%by weight based on the total weight of a layer in which the adsorbent iscontained. More preferably, the inner layer comprises the adsorbent inan amount which is least 20% by weight based on the total weight of alayer in which the adsorbent is contained.

Preferably, the article comprises an amount of a buffering agent whichranges from 2 to 5% by weight based on the total weight a layer in whichthe buffering agent is contained. More preferably, the amount ofbuffering agent ranges from 3 to 4% by weight.

The objects of another aspect of the present invention are achieved byproviding a method of preserving an archival document or object,comprising storing the archival document or object in proximity to amixture containing a buffer and an adsorbent. The buffer and theadsorbent can be an integral portion of a container in which thearchival document or object is stored. Alternatively, the buffer, theadsorbent or a mixture comprising the buffer and the adsorbent can bestored within a container, and the archival document or object can alsobe stored within the container.

The objects of another aspect of the present invention are achieved byproviding an article such as artist's paper or canvas having a surfacesuitable for drawing or painting. The artist's paper may furthercomprise a vapor barrier, which may be located either within theartist's paper or on a side of the artist's paper opposite the surface.The vapor barrier would prevent harmful gases from affecting the mattedand framed art. The objects of yet another aspect of the presentinvention are achieved by providing a container with a removable dividerplate for selectively determining a dimension of the available storagespace to prevent the documents in the container from curling or bowingwhen the container is less than full of documents. The containerpreferably includes a box-shaped receptacle having a bottom, a frontwall, a back wall, and an opposing pair of side walls. An opposing pairof internal walls are positioned within the box-shaped receptaclegenerally parallel to and spaced from the pair of side walls, and atleast one opposing pair of substantially-vertical slots are formedwithin the pair of internal walls. The container further includes atleast one divider plate having an opposing pair of tabs extendingsubstantially perpendicularly from its opposing ends, wherein each tabis adapted to be received by a corresponding slot and positionedsubstantially parallel to and between a corresponding internal wall andside wall.

Preferably, the box-shaped receptacle and opposing pair of internalwalls are integrally formed from a single sheet blank of a materialwhich will not harm the archival documents to be stored inside. It isalso preferred that the container includes a cover hingedly attached tothe back wall to substantially seal the archival documents storedtherein.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are incorporated in and constitute apart of the specification, further illustrate the invention and,together with the description, serve to explain the principles of theinvention.

FIG. 1 is a layered material with a buffered inner layer and a vaporbarrier;

FIG. 2 is a layered material containing a buffer and an adsorbent;

FIG. 3 is an exploded orthographic view of a representative embodimentof the container and removable divider plate;

FIG. 4 is a front view of a representative embodiment of a single sheetblank for assembling the container of FIG. 3;

FIG. 5 is an orthographic view of a representative embodiment of acontainer having a buffer and/or adsorbent contained therein; and

FIG. 6 is a side view of a sheet of artist's paper containing a bufferand an adsorbent.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Reference will now be made in detail to the present preferredembodiments of the invention. In the example and throughout thespecification and claims, all parts and percentages are by weight unlessotherwise specified.

In accordance with an aspect of the invention, FIG. 1 illustrates alayered material. As here embodied, in FIG. 1, layers 1 and 2 are porouspaper formed on a cylinder paper machine. Layer 1 is the outermost layerdeposited by the machine cylinder. It forms the inside of an archivalbox. Layer 1 can contain alkaline buffering or could be a neutral pH,non-buffered layer. It can optionally contain activated charcoal.Preferably, it is highly porous and is made from fibers such aseucalyptus or other fibers having like properties. Layer 2 is depositedon the paper layer by other cylinders and contains activated carbon asan adsorbent and calcium carbonate as a buffer. Layers 1 and 2 form acontinuous sheet of paper, and are not separated by an adhesive as theywould be in a laminated sheet.

Layer 3 is a barrier layer formed from metallized polyester. It willprevent the passage of vapor through the final product. It is laminatedto layers 2 and 4. Layer 4 forms the exterior of a container. It is madefrom a strong, high density paper having good durability and archivalcharacteristics. It is preferably made in a non-acidic paper system andhas an alkaline pH. It contains an alkaline buffering material such ascalcium carbonate, and uses a neutral or alkaline (i.e., non-acidic)sizing.

The layered material of FIG. 1 can be formed in varying thicknesses,densities and paper fiber compositions. It can be used for art paper,file folders, envelopes, mats, mounting boards or as a container forstoring papers which are to be preserved in their original state for anextended period of time.

In accordance with an aspect of the invention, FIG. 2 represents anon-laminated multi-layer paper which can be used for interior housingssuch as envelopes, file folders, interleaving papers, album pages,artist papers, mats, mounting boards and papers, permanent records orother objects where the preservation of the paper in its original stateis desired.

In FIG. 2, layer 10 is the interior surface and can be the interior ofan envelope, box or file folder. Layer 10 could also be the surface ofan artist's paper which would accept the medium in use such as watercolor, ink, paint or chalk. In that case, FIG. 2 represents a sectionalview of an artist's paper.

Layer 10 is preferably made in a non-acid papermaking system andpreferably is free of or substantially free of lignin and sulfur. Itpreferably has a pH in the neutral to alkaline range and contains analkaline buffer such as calcium carbonate. In some circumstances, it maybe desirable for this layer to have a neutral pH and not containalkaline buffers. Such circumstances would include cases where a proteinbased material is to be stored in or maintained next to this layer. Inother circumstances, it may be desirable to include both an adsorbentsuch as activated carbon and an alkaline buffer such as calciumcarbonate in layer 10. Layer 10 preferably has a high porosity, so thatharmful substances can easily pass into and be absorbed by this layer.

Layer 20 is a non-laminated layer. This layer contains an adsorbent suchas activated carbon and an alkaline buffer such as calcium carbonate. Itis preferably made in a non-acidic papermaking system and is preferablyfree of or substantially free of lignin and sulfur. It preferably has apH which ranges from neutral to alkaline.

Layer 30 is an exterior layer of the material. It could form theexterior layer in a housing such as an envelope, box or file folder, orthe back of a sheet of paper. If this laminated material were to be usedas an artist's paper, layer 30 would represent the side on which theartist would not draw or paint. Layer 30 can contain an adsorbent suchas activated carbon and an alkaline buffer such as calcium carbonate. Itmay also contain alkaline buffer alone. It is preferably made in anon-acidic papermaking system and is preferably free from orsubstantially free from lignin, sulfur and similar undesirablematerials. Layer 30 preferably has a pH in the neutral to alkalinerange. If layer 30 is to form the exterior of a housing such as anenvelope, box or folder, it preferably has a high density and gooddurability and surface strength. If this layer is to be colored,non-bleeding permanent colors should be used.

The multilayered structures of FIGS. 1 and 2, as well as otherstructures within the scope of the present invention, can be made byprocesses which are substantially similar to those disclosed in U.S.Patent No. 4,489,120, the disclosure of which is totally incorporatedherein by reference. The adsorbent and the buffer can be added to theinner layers of the structure by mixing appropriate amounts of them withthe slurry from which the inner layers are to be formed.

In a preferred method, webs are formed by blending fibers that are cutand fibrillated. Fibrillation develops fibrils which can mechanicallyentrap fillers, pigments or surface active materials, such as buffersand/or adsorbents. The retention produced by this mechanism can be 50%to 60%. When the fiber mat is formed, entanglement of fibers of varyinglengths can increase retention to 70% to 80% by fibrillation.

The total retention can be chemically increased to 90% to 98%. Certainchemical combinations such as latex and charged water soluble polymerscan produce co-precipitation and agglomeration of polymer surface activefillers and cellulose fibrils. Another possible mechanism involves theelectrokinetic attachment of charged water soluble polymers to cellulosefibers. The surface active fillers then attach to the charged polymers.Yet another possible mechanism involves the addition of polymers to forma protective colloid with polymers being attached to the surface activefiller. The protective colloid can then attach to fiber surfaces. Thesurface activity of the protective colloid is not significantlydiminished; thus, the surface active fillers or pigment can maintain ahigh level of activity for absorption of gases of acidic materials thatcause deterioration. The polymer combinations may also result in abinding of the surface active filler or pigment, such as activatedcharcoal and alkaline buffers like calcium carbonate, into the finished,dried fibrous web. The physical and chemical retention mechanisms areusually synergistic, resulting in high retention levels of over 95%. Theremaining percentage is lost in the white water of the paper machine.

The adsorbent is preferably selected from activated carbon, activatedcharcoal, or similar carbon-containing adsorbent materials. It may alsobe possible to use an inorganic adsorbent such as silica, activatedalumina, or a molecular sieve or zeolite. Inorganic adsorbents alsoadsorb water vapor, and should only be used in situations where thisproperty will not pose a substantial problem.

The buffer is preferably selected from calcium carbonate, magnesiumbicarbonate and mixtures thereof. However, other alkali and alkalineearth carbonates, bicarbonates, hydroxides, like compounds and mixturesthereof can also be used. Moreover, the buffer could be incorporated inthe various layers by performing a deacidification process for asufficient length of time such that excess deacidifying agent isintroduced into the layers.

Each of the layers described herein (other than the vapor barrier) ispreferably made from fully bleached alpha cellulose pulp. The layers arepreferably free of lignin, ground wood, waxes, plasticizers, reduciblesulphur, oxidizing chemicals and potentially harmful non-celluloseproducts. The sulphur content is preferably less than 0.0008% reduciblesulphur as per ASTMD 984-74 or Tappi 406, su 72. The layers arepreferably non-tarnishing as per accelerated tarnishing test ASTMD2043-69 and Tappi T 444, T 564. The layers are preferably free ofparticles of metal. Alkaline sizing is preferably used. The surface ofthe layers is preferably smooth and free from knots, shives and abrasiveparticles. If it is desired to produce a less expensive product, thelayers can contain lignin. They can also be made from recycled paper.

The outer surface container preferably shows a maximum fiber loss ofone-tenth of one percent after 100 cycles according to Tappi 476. Thesmoothness is preferably a minimum of 195 Sheffield units followingTappi UM-518 test. The outer portion of the container will preferablywithstand a minimum of 1,000 double folds in the weakest direction at 1kg load after conditioning according to Tappi 511. The outer portion ofthe container preferably has a minimum Elmendorf internal tearresistance of 350 gr. per sheet after conditioning according to Tappi T414. The outer portion of the container preferably has 2800 stiffnessunits in the machine direction and 1400 stiffness units in the crossdirection according to Tappi 489. The bursting strength of the outerportion of the container is preferably at least 300 psi when tested inaccordance with Tappi T 807.

When measured according to Tappi T-460-os-68 (the Gurley porosity test),the inner layers preferably will have a Gurley porosity figure of lessthan 100 sec/100 cc of air, and more preferably of between 5 sec/100 ccand 70 sec/100 cc. The outer layer preferably has a Gurley porosity ofbetween 200 sec/100 cc and 1000 sec/100 cc. The vapor barrier is, ofcourse, not porous, since it is used to prevent pollutants such asNO_(x), SO₂, ozone, peroxides and similar harmful compounds fromentering the container.

In accordance with another aspect of the invention, FIG. 5 is anorthographic view of a representative embodiment of a container having abuffer and/or adsorbent contained therein. The container preferably hasa top 510, a body 520 and may contain a solid object 530 comprising thebuffer and/or adsorbent. The buffer and/or adsorbent can in addition orinstead be an integral part of the top 510 and/or body 520.

In accordance with another aspect of the invention, FIG. 6 represents asectional view of an artist's paper. Layer 610 represents the surface ofan artist's paper which would accept the medium in use such as watercolor, ink, paint or chalk.

Layer 620 is a non-laminated layer. This layer contains an adsorbentsuch as activated carbon and an alkaline buffer such as calciumcarbonate. It is preferably made in a non-acidic papermaking system andis preferably free of or substantially free of lignin and sulfur. Itpreferably has a pH which ranges from neutral to alkaline.

Layer 630 is an exterior layer of the material, and could also representa side on which the artist would draw or paint, if a two sided artist'spaper was desired. Layer 630 can contain an adsorbent such as activatedcarbon and an alkaline buffer such as calcium carbonate. It may alsocontain alkaline buffer alone. It is preferably made in a non-acidicpapermaking system and is preferably free from or substantially freefrom lignin, sulfur and similar undesirable materials. Layer 630preferably has a pH in the neutral to alkaline range. If this layer isto be colored, non-bleeding permanent colors should be used.

In accordance with another aspect of the invention, the container can beconfigured to permit the long term storage of archival documents withoutslippage of the archival documents or the resulting deformation.

The container is preferably made from archival material, preferably thearchival material described in detail above. It preferably includes abox-shaped receptacle having a removable divider plate for selectivelydetermining a dimension of the available storage space. Morespecifically, and as best seen in FIGS. 3 and 4, the container 100 mayinclude a box-shaped receptacle 110 having a bottom 112, a front wall114, a back wall 116, and an opposing pair of side walls 118. Anopposing pair of internal walls 120 can be positioned within thebox-shaped receptacle 110 generally parallel to and spaced from the pairof side walls 118. As seen in FIG. 3, at least one opposing pair ofsubstantially-vertical slots 122 can be formed within the pair ofinternal walls 120.

The container may further include at least one divider plate 130 havingan opposing pair of tabs 132 extending substantially perpendicularlyfrom its opposing ends. Each tab 132 can be adapted to be received by acorresponding slot 122 and positioned substantially parallel to andbetween a corresponding internal wall 120 and side wall 118, as bestseen in FIG. 3. The tabs 132 can face either the front or the back ofthe container, depending on which side of the container will be moreheavily loaded. More specifically, the divider plate 130 is adapted suchthat the opposing pair of tabs may be slid substantially vertically intoengagement with the slots 122 formed in the opposing pair of internalwalls 120. As such, it should be evident that by providing a pluralityof pairs of slots, selective adjustment of a dimension of availablestorage space within the container can be greatly enhanced to preventthe documents in the container from curling or bowing when the containeris less than full of documents. Further, it is preferable to form theslots 124 with V-shaped entries 124 to facilitate easier insertion ofthe divider plate 130 within the slots 124.

In the preferred embodiment of the container, the box-shaped receptacle110 and opposing pair of internal walls 120 are integrally formed from asingle sheet blank 101 of the material of the invention set forth above.FIG. 4 presents a representative embodiment of such a single sheet blank101. As seen in FIG. 4, the single sheet blank is divided by a series ofliving hinges 105 to form the bottom portion 112, the bottom tabs 113,front wall portion 114, the back wall portion 116, the side wall portion118, and the internal wall portions 120.

To assemble the container 100, the bottom tab portions 113 are firstfolded perpendicular to the side wall portions 118, and the internalwall portions 120 are folded perpendicular to the front wall portion114. The side wall portions 118 are then folded perpendicular to theback wall portion 116, and both the front wall portion 114 and the backwall portion 116 are then folded perpendicular to the bottom portion 112and substantially parallel with each other. As such, the forward edgesof the side wall portions 118 may then be attached to the outer edges ofthe front wall portion 114, with the internal wall portions 120extending within the box-shaped receptacle generally parallel to andspaced from the pair of side walls portions 118. Conventional stripstaples 121 or other fasteners may be used to attach the walls alongtheir edges. A conventional label opening 119 and a wire handle 123 mayalso be added. Modifications may be made to the single sheet blank tovary the shape of the box-shaped receptacle, as desired, into othersizes or shapes such as trapezoidal portions for a pyramidal shape.

Similarly, the divider plate 130 and opposing pair of tabs are alsopreferably formed from the single sheet blank. As seen in FIG. 4, thedivider plate may be formed in a variety of shapes, such as a widerdivider plate 130 for greater stability or a thinner divider plate 130'for reduced material costs.

As seen in FIG. 3, the container embodied herein also includes a cover140 hingedly attached to the back wall 116 of the box-shaped receptaclefor substantially sealing the archival documents stored therein. FIG. 4shows that the cover may likewise be integrally formed from the singlesheet blank 101 of material described above. The cover 140 includes acover top portion 142, a cover front wall portion 144, and cover sidewall portions 148. As with the box-shaped receptacle 110, the cover 140is assembled simply by folding the portions along the living hinges 105and securing the front edges of the cover side wall portions 148 to theouter edges of the cover front wall portion 144.

Preferably, the receptacle 110, the divider plate 130, or both thereceptacle 110 and the divider plate 130 comprise a buffer, an adsorbentor a combination thereof. The receptacle 110, the divider plate 130, orboth the receptacle 110 and the divider plate 130 may be formed from thearticle or layered material described above.

EXAMPLE

In this example, the effects of a composition comprising a buffer, anadsorbent or a combination thereof were tested in experiments involvingthe preservation of alkaline paper samples in an accelerated agingprocess. In these experiments, individual sheets comprising cellulosefibers and optionally including the adsorbent and/or the buffer wereprepared by forming a slurry of a fiber blend and the adsorbent and/orthe buffer, and dispersing the slurry in water. The diluted anddispersed slurry was then placed in a sheet mold. This sheet mold had awire mesh screen at its base. The slurry in the sheet mold was mildlyagitated, and the sheet mold was then drained. As the water drainedthrough the wire mesh screen, the fiber and the adsorbent and/or bufferwas collected as a mat on the screen. Next, a blotter was placed on theresulting wet fiber mat in order to remove excess water. The blotter wasthen used to peel the fiber mat away from the wire mesh screen. Next,the mat was sandwiched between two cloth felts and mechanically pressedto remove water. The pressed mat was then dried on a dryer can to form asheet having a moisture content of between five and ten percent.

Nine paper samples, having the adsorbent and buffer content specified inthe following table, were prepared according to the above-notedprocedure. The porosity of samples 1-9 was measured by determining theamount of time required to force 100 cc of air through the samples. Theresults of these measurements are shown in the following table.

Each of these samples was then tested by placing one sheet of the samplein a metallized polyester container, along with five sheets of paperfrom a book. The book paper had an alkaline pH. After sealing thesamples and the book paper inside of the metallized polyester container,the sealed container was aged for 88 hours at a temperature of 100° C.

The book paper was then removed from the polyester container andsubjected to various tests. The tensile strength, elongation, resistanceto repeated folding under load and the pH of the book papers weremeasured. The tensile strength of the aged book papers was measuredusing an Instron pendulum type tester by following Tappi method T 404 om87. The resistance of the book paper to repeated folding under load wasmeasured by using the standard MIT fold test. In this test, the sheetsof book paper were placed under a 1 kg. load. The sheets of paper wererepeatedly folded through opposing 180° angles until they failed. Thedata in the following table represents the average number of folds whichthe paper endured prior to tearing. The pH of the book paper wasmeasured by grinding a sample of the book paper and mixing it with 200ml of deionized water. The pH of the mixture was then measured using aFisher Accumet Model 630 pH meter calibrated with a buffer at a pH of 4,7 and 10.

The fold data shown in this table demonstrates that samples containingbuffer are effective in preserving book paper. Samples containing acombination of adsorbent and buffer are substantially and unexpectedlymore effective at preserving the book paper than those samplescontaining either of the adsorbent or the buffer alone. The synergisticbenefits produced by the combination of the adsorbent and the buffer aresubstantially greater than what would have been predicted by simplycombining the improvements produced by using either the adsorbent or thebuffer alone.

The beneficial effects produced by the combination of adsorbent andbuffer are particularly surprising because alkaline book paper isgenerally quite resistant to decomposition. Thus, it would not have beenexpected that such a substantial reduction in the decomposition of thebook paper would have been achieved.

    ______________________________________                                        Pa-                                    MIT                                    per  %                                 Fold                                   Sam- Actv.   %       Poros-      Elon- 1 Kg. pH                               ple  C       CaCO.sub.3                                                                            ity   Tensile                                                                             gation                                                                              Load  T-cold                           ______________________________________                                        1    20      0       44    7.23  3.73  4.4   7.39                             2    0       3       95    6.55  3.54  4.0   7.13                             3    0       0       92    7.15  3.58  3.5   7.40                             4    0       3       34    7.40  3.95  4.0   7.40                             5    20      3       15    7.40  3.95  7.8   7.52                             6    0       0       40    5.72  3.12  2.6   7.47                             7    15      3       15    7.47  3.79  6.6   7.75                             8    10      3        9    7.33  3.89  5.2   7.75                             9    5       3       10    6.88  3.71  5.0   7.15                             ______________________________________                                    

It will be apparent to those skilled in the art that variousmodifications and variations can be made in the present inventionwithout departing from the scope or spirit of the invention. Thus, it isintended that the present invention cover the modifications andvariations of this invention provided they come within the scope of theappended claims and their equivalents.

What is claimed is:
 1. A layered archival preservation material for thepreservation of archival documents and objects, said layered materialcomprising:a first layer comprising an alkaline buffer or a deacidifyingagent; a second layer comprising an alkaline buffer or a deacidifyingagent; a vapor barrier positioned between said first layer and saidsecond layer, wherein said vapor barrier prevents the passage of vaporthrough said layered archival preservation material, and wherein eithersaid first layer or said second layer additionally contains anadsorbent.
 2. The layered material of claim 1, wherein said first layeris buffered with calcium carbonate, magnesium bicarbonate or a mixturethereof.
 3. The layered material of claim 1, wherein said second layeris buffered with calcium carbonate, magnesium bicarbonate or a mixturethereof.
 4. The layered material of claim 1, wherein said vapor barriercomprises a layer of polyester.
 5. The layered material of claim 4,wherein said polyester is metallized.
 6. The layered material of claim1, wherein both said first layer and said second layer contain anadsorbent.
 7. The layered material of claim 1, wherein said adsorbent isactivated carbon.
 8. The layered material of claim 1, wherein said firstlayer comprises at least 10% by weight of said adsorbent based on thetotal weight of said first layer.
 9. The layered material of claim 1,wherein said first layer comprises said adsorbent in an amount of atleast 20% by weight based on the total weight of said first layer. 10.The layered material of claim 1, wherein said first layer comprises anamount of a buffering agent which ranges from 2 to 5% by weight based onthe total weight of said first layer.
 11. The layered material of claim1, wherein said amount of buffering agent ranges from 3 to 4% by weight.12. The layered material of claim 1, wherein said second layer has asmooth and durable finish.
 13. The layered material of claim 1, whereinsaid second layer comprises fibers of northern softwoods.
 14. Thelayered material of claim 1, further comprising a porous layer, whereinsaid first layer is positioned between said porous layer and said vaporbarrier.
 15. The layered material of claim 1, wherein said porous layeris substantially free of said adsorbent.
 16. The layered material ofclaim 1, wherein said porous layer contains a buffer.
 17. The layeredmaterial of claim 1, wherein said porous material comprises eucalyptusfibers.
 18. The layered material of claim 1, wherein said first layer,said second layer or both said first layer and said second layer has apH ranging from neutral to alkaline.
 19. The layered material of claim1, wherein said first layer, said second layer or both said first layerand said second layer has a pH ranging from 8.5 to 9.2.
 20. The layeredmaterial of claim 1, further comprising a layer of flame resistantmaterial.
 21. The layered material of claim 1, wherein said first layer,said second layer, or both said first layer and said second layercomprise paper.
 22. The layered material of claim 1, wherein said firstlayer, said second layer, or both said first layer and said second layercomprise alpha-cellulose.
 23. The layered material of claim 1, whereinsaid adsorbent is a molecular sieve.
 24. The layered material of claim23, wherein said molecular sieve is a zeolite.
 25. A preserved archivaldocument or object comprising an archival document or object incombination with a layered preservation material, such that saidarchival document or object is placed in contact with or in closeproximity to said layered preservation material, and wherein saidlayered material comprises a first layer having an alkaline buffer or adeacidifying agent, a second layer having an alkaline buffer ordeacidifying agent, and a vapor barrier positioned between said firstand said second layer, wherein said vapor barrier layer prevents thepassage of vapor through said layered material and wherein either saidfirst layer or said second layer further comprises an adsorbent.
 26. Amatting board for the preservation of an archival document or object,said board comprisinga first layer having an alkaline buffer or adeacidifying agent; a second layer having an alkaline buffer ordeacidifying agent; a vapor barrier positioned between said first andsaid second layer, wherein said vapor barrier layer prevents the passageof vapor through said board and wherein either said first layer or saidsecond layer further comprises an adsorbent.
 27. A mounting board forthe preservation of an archival document or object, said boardcomprisinga first layer having an alkaline buffer or a deacidifyingagent; a second layer having an alkaline buffer or deacidifying agent; avapor barrier positioned between said first and said second layer,wherein said vapor barrier layer prevents the passage of vapor throughsaid board and wherein either said first layer or said second layerfurther comprises an adsorbent.